1. Field of the Invention
This invention relates to containers for highly corrosive solutions and more particularly to containers for use in the electrolytic refinement or electrowinning of metals such as for example, copper, cobalt, nickel and zinc.
The electrolytic refining process for various metals results in the deposition of by-products on the floor of the electrolytic container. The by-products are known by those skilled in the art as "slimes". The slimes include precious metals, such as for example, gold and silver, and impurities contained in the electrolyte. These by-products over time accumulate as a slurry on the floor of the electrolytic container. Up until the present invention, removal of the slimes from the container involved removing the cathodes and anodes (i.e., the electrodes) contained within the electrolytic container, decanting the liquid electrolyte in the container above the slimes and then draining the slimes from the bottom floor of the container. Prior to the present invention, removal of the slimes, involved stopping the entire electrolytic process to accomplish the removal of the accumulated precious metals and salt impurities that accumulated on the bottom of the electrolytic container. As will be understood by those skilled in the art, the slimes were required to be removed in the course of the electrolytic process to prevent the deposition of the slimes on the cathode. Deposition of the slimes on the cathode results in a drop in the purity of the metal to be produced by the electrolytic process. Interruption of the electrolytic process to accomplish slime removal reduces the efficiency and the productivity of the electrolytic plant. Removal of the electrodes and electrolyte from the electrolytic container and the manual washing of the electrolytic container makes the process of removing slimes labor-intensive and subjects individuals carrying out these tasks to various health hazards due to the potential for contact with the corrosive liquid electrolyte.
The present invention provides a track assembly and electrolytic container for the automated removal of the slimes from the bottom of the container while the electrolytic process carried out in the container remains operational. Thus, manual labor of removing the electrodes and electrolyte and washing of the container is minimized and/or substantially eliminated along with the above-mentioned health risks.
2. Brief Description of the Background Art
U.S. Pat. No. 5,066,379 ('379 Patent) discloses a container for corrosive material. The '379 Patent discloses an electrolytic container formed of polymer concrete having an integrally molded overflow box, inlet channel, decanting passage, discharge pipe and drain hole. This patent discloses that sludge on or near the bottom of the container is drained from the container through a normally plugged drain hole. The '379 Patent sets forth that the bottom of the container is sloped from one side and one end or both sides and one end to facilitate the removal of sludge.
PCT/F198/00655 ('655 Application) entitled, "Separating Member for Separating the Tank Bottom Part from the Rest of the Tank" discloses a separating member for separating the bottom part of an electrolytic tank from the rest of the tank in connection with the removal of solids settled onto the bottom of the electrolytic tank. The '655 Application discloses support and control members installed in the electrolytic tank which form the trajectory of the separating member. In contrast, the present invention provides an integrally molded container allowing engagement of the track without mechanical fasteners that can corrode or create unacceptable stresses in the polymer composite of the electrolytic container construction.
While the above-mentioned background art electrolytic containers and separating members are known, they do not disclose an electrolytic container having the unique integrally molded lip and trough section embodiments of the present invention, nor is the background art concerned with providing a track assembly and an electrolytic container having a constant and uniform cross-section of the track slot from the entry point at the top of the electrolytic container through the vertical path, the curved elbow transition section, and horizontal path of the lip and trough section of the shell as described herein by the present invention.
Therefore, in spite of this background material, there remains a very real and substantial need for an electrolytic container having an integrally molded shell and track assembly capable of mechanically engaging and guiding a bendable separating member providing for the separation of the slimes on the bottom of the electrolytic container from the electrolyte that is in the rest of the electrolytic container. Having the separating member in place and engaged in the track assembly of this invention provides for the elimination of the slimes from the electrolytic container during active operation of the electrorefining process.